Organic light-emitting display apparatus and method of manufacturing the same

ABSTRACT

An organic light-emitting display apparatus including a substrate; a display unit which defines an active area of the substrate and includes a thin film transistor; concave-convex portions protruded from the substrate in an area outside the active area; and an encapsulation layer which encapsulates the display unit. The thin film transistor includes an active layer, a gate insulating layer on the active layer, a gate electrode, a source electrode, a drain electrode, and an interlayer insulating layer between the gate electrode and the source electrode, and between the gate electrode and the drain electrode. The concave-convex portions include portions of the gate insulating layer and the interlayer insulating layer, and the encapsulation layer covers the concave-convex portions.

This application claims priority to Korean Patent Application No.10-2013-0102658, filed on Aug. 28, 2013, and all the benefits accruingtherefrom under 35 U.S.C. §119, the disclosure of which is incorporatedherein in its entirety by reference.

BACKGROUND

1. Field

One or more exemplary embodiment of the invention relate to an organiclight-emitting display apparatus and a method of manufacturing the same,and more particularly, to an organic light-emitting display apparatusincluding a thin film encapsulation layer having an improvedencapsulation characteristic and a method of manufacturing the organiclight-emitting display apparatus.

2. Description of the Related Art

An organic light-emitting display apparatus is a self-emissive displayapparatus having an organic light-emitting device. The organiclight-emitting device includes a hole injection electrode and anelectron injection electrode, and an organic emission layer (organicEML) therebetween. A hole injected from the hole injection electrode andan electrode injected from the electron injection electrode are combinedin the organic EML so that an exciton is generated from the combinationand emits light when the exciton transitions from an exited state to aground state.

The organic light-emitting display apparatus that is a self-emissivedisplay apparatus does not require a separate light source, is capableof operating with a relatively low voltage, is capable of having arelatively light weight and slimness, and is expected to become a nextgeneration display apparatus due to high display quality characteristicssuch as a wide viewing angle, high contrast and a fast response time.

SUMMARY

One or more exemplary embodiment of the invention include an organiclight-emitting display apparatus including a thin film encapsulationlayer having an improved encapsulation characteristic and a method ofmanufacturing the organic light-emitting display apparatus.

Additional features will be set forth in part in the description whichfollows and, in part, will be apparent from the description, or may belearned by practice of the exemplary embodiments described herein.

According to one or more exemplary embodiment of the invention, anorganic light-emitting display apparatus includes a substrate; a displayunit which defines an active area of the substrate and includes a thinfilm transistor; concave-convex portions protruded from the substrate inan area outside the active area; and an encapsulation layer whichencapsulates the display unit. The thin film transistor includes anactive layer, a gate insulating layer on the active layer, a gateelectrode, a source electrode, a drain electrode, and an interlayerinsulating layer between the gate electrode and the source electrode,and between the gate electrode and the drain electrode. Theconcave-convex portions include portions of the gate insulating layerand the interlayer insulating layer, and the encapsulation layer coversthe concave-convex portions.

Each of the concave-convex portions may have a double-layer structureincluding the portions of the gate insulating layer and the interlayerinsulating layer.

The encapsulation layer may include an inorganic layer, and theinorganic layer may contact the concave-convex portions.

The inorganic layer and the interlayer insulating layer may include asame material.

The inorganic layer and the gate insulating layer may include a samematerial.

The encapsulation layer may include a stacked structure including anorganic layer and an inorganic layer, and the inorganic layer maycontact the concave-convex portions.

The stacked structure may include more than one of the organic layer orthe inorganic layer.

The inorganic layer and the interlayer insulating layer may include asame material.

The inorganic layer and the gate insulating layer may include a samematerial.

The organic light-emitting display apparatus may further include aprotective layer between the encapsulation layer and the display unit.

According to one or more exemplary embodiment of the invention, anorganic light-emitting display apparatus includes a substrate; a displayunit which defines an active area of the substrate and includes a thinfilm transistor and an organic light-emitting device electricallyconnected to each other; and an encapsulation layer which encapsulatesthe display unit. The thin film transistor includes a gate insulatinglayer extending to an area outside the active area, and an interlayerinsulating layer on the gate insulating layer and extending to the areaoutside the active area. Protruding portions are between the gateinsulating layer and the interlayer insulating layer in the area outsidethe active area. The concave-convex portions are defined by theinterlayer insulating layer in the area outside the active area, and theencapsulation layer covers the concave-convex portions.

Each of the stepped portions may include a metal layer.

The thin film transistor may further include an active layer, a gateelectrode, a source electrode and a drain electrode. The interlayerinsulating layer may be between the gate electrode and the sourceelectrode, and between the gate electrode and the drain electrode. Thedisplay unit may further include an organic light-emitting deviceincluding a pixel electrode connected to the source electrode or thedrain electrode; an intermediate layer on the pixel electrode andincluding an organic emission layer; and an opposite electrode on theintermediate layer. The protruding portions may include a same materialas that of the gate electrode, the source electrode, the drain electrodeor the pixel electrode.

The encapsulation layer may include an inorganic layer, and theinorganic layer may contact the concave-convex portions.

The inorganic layer and the interlayer insulating layer may include asame material.

The encapsulation layer may have a stacked structure including anorganic layer and an inorganic layer, and the inorganic layer maycontact the concave-convex portions.

The stacked structure may include more than one of the organic layer orthe inorganic layer.

The inorganic layer and the interlayer insulating layer may include asame material.

The inorganic layer and the interlayer insulating layer may each includesilicon nitride (SiNx).

The organic light-emitting display apparatus may further include aprotective layer between the encapsulation layer and the display unit.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other features will become apparent and more readilyappreciated from the following description of the exemplary embodiments,taken in conjunction with the accompanying drawings of which:

FIG. 1 is a plane view illustrating an exemplary embodiment of anorganic light-emitting display apparatus according to the invention;

FIG. 2 is a cross-sectional view of the organic light-emitting displayapparatus of FIG. 1, taken along line II-II′;

FIG. 3 is a cross-sectional view of the organic light-emitting displayapparatus of FIG. 1, taken along line III-III′;

FIG. 4 is a magnified cross-sectional view illustrating portion P1 ofFIG. 3;

FIG. 5 is a plane view illustrating another exemplary embodiment of anorganic light-emitting display apparatus according to the invention;

FIG. 6 is a cross-sectional view of the organic light-emitting displayapparatus of FIG. 5, taken along line VI-VI′;

FIG. 7 is a cross-sectional view of the organic light-emitting displayapparatus of FIG. 5, taken along line VII-VII′; and

FIG. 8 is a magnified cross-sectional view illustrating portion P2 ofFIG. 7.

DETAILED DESCRIPTION

Reference will now be made in detail to exemplary embodiments, examplesof which are illustrated in the accompanying drawings. In this regard,the exemplary embodiments may have different forms and should not beconstrued as being limited to the descriptions set forth herein.Accordingly, the exemplary embodiments are merely described below, byreferring to the figures, to explain features of the invention. In thedrawings, the size and relative sizes of layers and regions may beexaggerated for clarity.

It will be understood that when an element or layer is referred to asbeing “on” or “connected to” another element or layer, the element orlayer can be directly on or connected to another element or layer orintervening elements or layers. In contrast, when an element is referredto as being “directly on” or “directly connected to” another element orlayer, there are no intervening elements or layers present. As usedherein, connected may refer to elements being physically and/orelectrically connected to each other. Like numbers refer to likeelements throughout. As used herein, the term “and/or” includes any andall combinations of one or more of the associated listed items.

It will be understood that, although the terms first, second, third,etc., may be used herein to describe various elements, components,regions, layers and/or sections, these elements, components, regions,layers and/or sections should not be limited by these terms. These termsare only used to distinguish one element, component, region, layer orsection from another element, component, region, layer or section. Thus,a first element, component, region, layer or section discussed belowcould be termed a second element, component, region, layer or sectionwithout departing from the teachings of the invention.

Spatially relative terms, such as “below,” “above,” and the like, may beused herein for ease of description to describe the relationship of oneelement or feature to another element(s) or feature(s) as illustrated inthe figures. It will be understood that the spatially relative terms areintended to encompass different orientations of the device in use oroperation, in addition to the orientation depicted in the figures. Forexample, if the device in the figures is turned over, elements describedas “below” relative to other elements or features would then be oriented“above” relative to the other elements or features. Thus, the exemplaryterm “below” can encompass both an orientation of above and below. Thedevice may be otherwise oriented (rotated 90 degrees or at otherorientations) and the spatially relative descriptors used hereininterpreted accordingly.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a,” “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises,”“comprising,” “includes” and/or “including,” when used in thisspecification, specify the presence of stated features, integers,operations, elements, and/or components, but do not preclude thepresence or addition of one or more other features, integers, steps,operations, elements, components, and/or groups thereof. Expressionssuch as “at least one of,” when preceding a list of elements, modify theentire list of elements and do not modify the individual elements of thelist.

Embodiments of the invention are described herein with reference tocross-section illustrations that are schematic illustrations ofidealized embodiments (and intermediate structures) of the invention. Assuch, variations from the shapes of the illustrations as a result, forexample, of manufacturing techniques and/or tolerances, are to beexpected. Thus, embodiments of the invention should not be construed aslimited to the particular shapes of regions illustrated herein but areto include deviations in shapes that result, for example, frommanufacturing.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

Since an organic light-emitting display apparatus may deteriorate due toexternal moisture or oxygen, the organic light-emitting device isencapsulated to be protected from external moisture or oxygen.

In order to obtain slimness and/or flexibility of the organiclight-emitting display apparatus, a thin film encapsulation (“TFE”) suchas including a plurality of inorganic layers or a plurality of layersincluding an organic layer and an inorganic layer, is used toencapsulate the organic light-emitting device.

The inorganic layer of the TFE may reduce or effectively preventpenetration of external moisture or oxygen, as a thickness of theinorganic layer is increased. However, when the thickness of theinorganic layer is increased, a stress of the inorganic layer isincreased such that the inorganic layer may be delaminated from otherlayers in the organic light-emitting display apparatus. When thedelamination of the inorganic layer occurs, external moisture or oxygenmay penetrate into the organic light-emitting device such that alifetime of the organic light-emitting display apparatus may bedecreased. Therefore, there remains a need for an improved organiclight-emitting display apparatus and organic light-emitting device inwhich delamination of the TFE is reduced and penetration of externalmoisture or oxygen is reduced or effectively prevented.

Hereinafter, the invention will be described in detail with reference tothe accompanying drawings.

FIG. 1 is a plane view illustrating an exemplary embodiment of anorganic light-emitting display apparatus 10 according to the invention.FIG. 2 is a cross-sectional view of the organic light-emitting displayapparatus 10 of FIG. 1, taken along line II-II′. FIG. 3 is across-sectional view of the organic light-emitting display apparatus 10of FIG. 1, taken along line III-III′. FIG. 4 is a magnifiedcross-sectional view illustrating portion P1 of FIG. 3.

Referring to FIGS. 1 through 4, the organic light-emitting displayapparatus 10 includes a substrate 101, a display unit 200 which definesan active area AA of the substrate 101 and/or the organic light-emittingdisplay apparatus 10, and an encapsulation layer 300 which encapsulatesthe display unit 200. The active area AA may be a display area while anarea outside the active area AA may be a peripheral or non-display area.

The substrate 101 may be a flexible substrate including a plasticmaterial such as polyimide, polyethylene terephthalate (“PET”),polycarbonate, polyethylene naphthalate, polyarylate (“PAR”),polyetherimide (“PEI”) or the like that have excellent heat-resistanceand durability. However, the invention is not limited thereto, and thesubstrate 101 may include various materials such as including metal,glass or the like.

The display unit 200 defines the active area AA of the substrate 101 orthe organic light-emitting display apparatus 10 and includes a thin filmtransistor TFT and an organic light-emitting device OLED that areelectrically connected to each other. A plurality of pad units 1 isdisposed around the active area AA, thereby transmitting an electricsignal from a power supply device (not shown) or a signal generationdevice (not shown) to the active area AA.

Hereinafter, the display unit 200 is described in detail with referenceto FIG. 3.

A buffer layer 201 may be disposed on the substrate 101. The bufferlayer 201 may be on an entire top surface of the substrate 101, e.g.,the buffer layer 201 may be disposed in the active area AA and an areaoutside of the active area AA. The buffer layer 201 may function toreduce or effectively prevent penetration of foreign substances via thesubstrate 101 and to provide a flat surface on the substrate 101. Thebuffer layer 201 may include various materials capable of performing theabove-described functions.

In one exemplary embodiment, for example, the buffer layer 201 may be acomposite layer of two or more layers such as an inorganic materiallayer including silicon oxide, silicon nitride, silicon oxynitride,aluminum oxide, aluminum nitride, titanium oxide, titanium nitride, orthe like, and an organic material layer including polyimide, polyester,acryl or the like.

The thin film transistor TFT may be disposed on the buffer layer 201.The thin film transistor TFT may include an active layer 202, a gateelectrode 204, a source electrode 206 and a drain electrode 207.

The active layer 202 may include an inorganic semiconductor such asamorphous silicon or polysilicon, an organic semiconductor, or an oxidesemiconductor. The active layer 212 may include a source region, a drainregion, and a channel region respectively corresponding to the source,drain and gate electrodes 206, 207 and 204.

A gate insulating layer 203 is disposed on the active layer 202. Thegate insulating layer 203 may correspond to the entire top surface ofthe substrate 101. That is, the gate insulating layer 203 may correspondto the active area AA and the area outside of the active area AA. Thegate insulating layer 203 may insulate the active layer 202 from thegate electrode 204. The gate insulating layer 203 may include an organicmaterial, or an inorganic material including SiNx, SiO₂, or the like.

The gate electrode 204 is disposed on the gate insulating layer 203. Thegate electrode 204 may include Au, Ag, Cu, Ni, Pt, Pd, Al, Mo, or analloy of Al:Nd or Mo:W. However, the invention is not limited thereto,and the gate electrode 204 may include various materials inconsideration of a design condition of the organic light-emittingdisplay apparatus 10.

An interlayer insulating layer 205 is disposed on the gate electrode204. The interlayer insulating layer 205 may correspond to the entiretop surface of the substrate 101. That is, the interlayer insulatinglayer 205 may correspond to the active area AA and the outer area of theactive area AA.

The interlayer insulating layer 205 is disposed between the gateelectrode 204 and the source electrode 206, and between the gateelectrode 204 and the drain electrode 207 so as to respectively obtaininsulation therebetween. The interlayer insulating layer 205 may includean inorganic material including SiNx, SiO₂, or the like.

Concave-convex portions 209 may be disposed in the area outside of theactive area AA. The concave-convex portions 209 may be disposed on thebuffer layer 201.

Each of the concave-convex portions 209 may have a double-layerstructure including the gate insulating layer 203 and the interlayerinsulating layer 205. In an exemplary embodiment of manufacturing theorganic light-emitting display apparatus 10, the concave-convex portions209 may be formed by patterning the gate insulating layer 203 and theinterlayer insulating layer 205. A region of the organic light-emittingdisplay apparatus 10 in which the concave-convex portions 209 are formedmay be considered to have an embossed shape. The concave-convex portions209 are covered by the encapsulation layer 300. Due to the repeatingprotruding and recessed shape defined by the concave-convex portions209, a contact area between the encapsulation layer 300 and each of thegate and interlayer insulating layers 203 and 205 is increased. Thus,adhesion between the encapsulation layer 300 and each of the gate andinterlayer insulating layers 203 and 205 is improved, so thatdelamination of the encapsulation layer 300 may be reduced oreffectively prevented, and by doing so, penetration of external moistureor oxygen to organic light-emitting device OLED may be efficientlyreduced or effectively prevented. Also, because portions of the gateinsulating layer 203 and the interlayer insulating layer 205 are absentbetween and around the concave-convex portions 209, a strain in andbelow the encapsulation layer 300 due to occurrence of a stress may bedecreased.

The source electrode 206 and the drain electrode 207 are disposed on theinterlayer insulating layer 205. In more detail, the interlayerinsulating layer 205 and the gate insulating layer 203 expose the sourceregion and the drain region of the active layer 202, and the sourceelectrode 206 and the drain electrode 207 respectively contact theexposed source and drain regions of the active layer 202. In anexemplary embodiment of manufacturing the organic light-emitting displayapparatus 10, the concave-convex portions 209 may be formed by a processin which the interlayer insulating layer 205 and the gate insulatinglayer 203 are formed to expose the source region and the drain region ofthe active layer 202, such that an additional process to form theconcave-convex portions 209 is omitted.

While FIG. 3 illustrates a top gate type thin film transistor TFT thatsequentially includes the active layer 202, the gate electrode 204, thesource electrode 206 and the drain electrode 207, the invention is notlimited thereto, and the gate electrode 204 may be disposed below theactive layer 202 in a bottom gate type thin film transistor TFT.

The thin film transistor TFT is electrically connected to the organiclight-emitting device OLED and drives the organic light-emitting deviceOLED. The thin film transistor TFT is covered by a passivation layer208.

The passivation layer 208 may include an inorganic insulating layerand/or an organic insulating layer. The inorganic insulating layer mayinclude SiO₂, silicon nitride (SiNx), silicon oxynitride (SiON), Al₂O₃,TiO₂, Ta₂O₅, HfO₂, ZrO₂, barium strontium titanate (“BST”), leadzirconate titanate (“PZT”) or the like, and the organic insulating layermay include polymer derivatives having a commercial polymer such aspoly(methyl methacrylate) (“PMMA”) and polystyrene (“PS) and a phenolgroup, an acryl-based polymer, an imide-based polymer, an allylether-based polymer, an amide-based polymer, a fluorine-based polymer, ap-xylene-based polymer, a vinylalcohol-based polymer or a combinationthereof. The passivation layer 208 may have a multi-layer structureincluding the inorganic insulating layer and the organic insulatinglayer.

The organic light-emitting device OLED may be disposed on thepassivation layer 208, and may include a pixel electrode 211, anintermediate layer 214 and an opposite electrode 215.

The pixel electrode 211 is disposed on the passivation layer 208. Inmore detail, the passivation layer 208 may expose a predetermined regionof the drain electrode 207 without covering an entire portion of thedrain electrode 207, and the pixel electrode 211 may be connected to theexposed portion of the drain electrode 207.

In the illustrated exemplary embodiment, the pixel electrode 211 may bea reflective electrode. The pixel electrode 211 may include a reflectivematerial layer including Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr or acombination thereof, and a transparent or translucent electrode layerdisposed on the reflective layer. The transparent or translucentelectrode layer may include indium tin oxide (“ITO”), indium zinc oxide(“IZO”), zinc oxide (“ZnO”), indium oxide (In₂O₃), indium gallium oxide(“IGO”) aluminum zinc oxide (“AZO”) or a combination thereof.

The opposite electrode 215 disposed to face the pixel electrode 211 maybe a transparent or translucent electrode. The opposite electrode 215may include a metal thin layer having a low work function and includingLi, Ca, LiF/Ca, LiF/Al, Al, Ag, Mg or a combination thereof. Also,opposite electrode 215 may include an auxiliary electrode layer or a buselectrode, which includes a transparent electrode forming material suchas ITO, IZO, ZnO, In₂O₃ or a combination thereof may be further disposedon the metal thin layer.

Thus, the opposite electrode 215 may transmit light emitted from anorganic emission layer (organic EML) included in the intermediate layer214. That is, the light emitted from the organic EML may be directlyemitted toward the opposite electrode 215, or may be reflected from thepixel electrode 211 as a reflective electrode and then emitted towardthe opposite electrode 215.

The organic light-emitting display apparatus 10 according to theinvention is not limited to a top-emission type organic light-emittingdisplay apparatus and alternatively may be a bottom-emission typeorganic light-emitting display apparatus in which light from the organicEML is emitted toward the substrate 101. In an exemplary embodiment ofthe bottom-emission type organic light-emitting display apparatus, thepixel electrode 211 may be a transparent or translucent electrode, andthe opposite electrode 215 may be a reflective electrode. Also, inanother alternative exemplary embodiment, the organic light-emittingdisplay apparatus 10 according to the illustrated exemplary embodimentmay be a dual-emission type organic light-emitting display apparatus inwhich light is emitted toward both top and bottom surfaces.

A pixel defining layer 213 including an insulating material is disposedon the pixel electrode 211. An opening defined in the pixel defininglayer 213 exposes a predetermined region of the pixel electrode 211, andthe intermediate layer 214 including the organic EML is disposed on theexposed region of the pixel electrode 211 and in the opening defined inthe pixel defining layer 213.

The organic EML may be a relatively small-molecule organic layer or apolymer organic layer. In addition to the organic EML, the intermediatelayer 214 may selectively further include a functional layer such as ahole transport layer (“HTL”), a hole injection layer (“HIL”), anelectron transport layer (“ETL”), an electron injection layer (“EIL”),or the like.

The encapsulation layer 300 is disposed on the opposite electrode 215.The encapsulation layer 300 may include a first inorganic layer 301, afirst organic layer 302 and a second inorganic layer 303. Also, aprotective layer 220 may be further disposed between the encapsulationlayer 300 and the display unit 200.

The protective layer 220 includes a capping layer 222 covering theopposite electrode 215, and a blocking layer 224 on the capping layer222.

The capping layer 222 may include an organic material such asN,N′-diphenyl-N,N′-bis(1-naphthyl)-1,1′-biphenyl-4,4″-diamine (“a-NPD”),N,N′-di(naphthalene-1-yl)-N,N′-diphthalbenzidine (“NPB”),N,N′-diphenyl-N,N′-bis(3-methylphenyl)-(1,1′-biphenyl)-4,4′-diamine(“TPD”), 4,4′,4″-Tris(N-3-methylphenyl-N-phenylamino)triphenylamine(“m-MTDATA”), tris(8-quinolinolato)aluminum (“Alq₃”) copperphthalocyanine (“CuPc”), or the like. The capping layer 222 may functionto protect the organic light-emitting device OLED and to help light,which is generated in the organic light-emitting device OLED, to beefficiently emitted from the organic light-emitting device OLED.

The blocking layer 224 may include an inorganic material such as lithiumfluoride (LiF), magnesium fluoride (MgF₂), calcium fluoride (CaF₂) orthe like. In an exemplary embodiment of manufacturing the organiclight-emitting display apparatus 10, the blocking layer 224 may functionto block plasma, which is used in forming the first inorganic layer 301,from penetrating into the organic light-emitting device OLED and thendamaging elements thereof such as the intermediate layer 214, theopposite electrode 215 or the like. In the illustrated exemplaryembodiment, the blocking layer 224 may include LiF having a pin-holestructure.

The first inorganic layer 301 is disposed on the protective layer 220.In one exemplary embodiment, for example, the first inorganic layer 301may include an aluminum oxide (AlOx). The first inorganic layer 301 mayhave a preset cross-sectional thickness, formed in an exemplaryembodiment of manufacturing the organic light-emitting display apparatus10 such as by a sputtering method.

The first organic layer 302 is disposed on the first inorganic layer 301and may have a preset cross-sectional thickness so as to planarize astep difference due to the pixel defining layer 213. The first organiclayer 302 may include epoxy, acrylate, urethane-acrylate or acombination thereof. A planar area of the first organic layer 302 may beless than that of the first inorganic layer 301.

The second inorganic layer 303 may surround the first inorganic layer301 and the first organic layer 302. That is, the first organic layer302 is completely surrounded by the first inorganic layer 301 and thesecond inorganic layer 303, so that penetration of external moisture oroxygen may be efficiently reduced or effectively prevented.

The second inorganic layer 303 may include SiNx and may have a presetcross-sectional thickness formed in an exemplary embodiment ofmanufacturing the organic light-emitting display apparatus 10 such as bychemical vapor deposition (“CVD”).

A planar area of the second inorganic layer 303 may be greater than thatof the first inorganic layer 301 and may directly cover theconcave-convex portions 209 in the area outside of the active area AA.

Also, the second inorganic layer 303 may include a same material as theinterlayer insulating layer 205 and/or be in same layer as theinterlayer insulating layer 2205. That is, in an exemplary embodiment ofmanufacturing the organic light-emitting display apparatus 10, when thesecond inorganic layer 303 is formed of SiNx and the interlayerinsulating layer 205 is also formed of SiNx, adhesion between the secondinorganic layer 303 and the interlayer insulating layer 205 may beimproved, so that adhesion between the second inorganic layer 303 andthe concave-convex portions 209 may be improved. In this manner, thesecond inorganic layer 303 has a cross-sectional thickness sufficient tocover particles, so that, although a layer stress is increased,delamination of the second inorganic layer 303 may be reduced oreffectively prevented, and by doing so, penetration of external moistureor oxygen to the organic light-emitting device OLED may be efficientlyreduced or effectively prevented.

Also, the second inorganic layer 303 may include a same material as thegate insulating layer 203. That is, in an exemplary embodiment ofmanufacturing the organic light-emitting display apparatus 10, when thesecond inorganic layer 303 is formed of SiNx and the gate insulatinglayer 203 is also formed of SiNx, adhesion between the second inorganiclayer 303 and the gate insulating layer 203 may be improved, so thatadhesion between the second inorganic layer 303 and the concave-convexportions 209 including portions of the gate insulating layer 203 may beimproved. In this manner, the second inorganic layer 303 has across-sectional thickness sufficient to cover particles, so that,although a layer stress is increased, delamination of the secondinorganic layer 303 may be reduced or effectively prevented, and bydoing so, penetration of external moisture or oxygen to the organiclight-emitting device OLED may be efficiently reduced or effectivelyprevented.

A second organic layer 304 and a third inorganic layer 305 may bedisposed on the second inorganic layer 303. Although not illustrated, afourth inorganic layer (not shown) including AlOx may be disposed on anexterior surface of the encapsulation layer 300.

The second organic layer 304 may include epoxy, acrylate,urethane-acrylate or a combination thereof, and may have a presetcross-sectional thickness. The second organic layer 304 may lessen alayer stress occurred in the first inorganic layer 301 and may evenlycover the particles or the like.

The third inorganic layer 305 covers the second organic layer 304. Thethird inorganic layer 305 contacts a top surface of the second inorganiclayer 303 in the area outside the active area AA.

The third inorganic layer 305 may include a same material as the secondinorganic layer 303. In one exemplary embodiment, for example, the thirdinorganic layer 305 may include SiNx. Thus, adhesion between the thirdinorganic layer 305 and the second inorganic layer 303 is improved, sothat penetration of external moisture or oxygen to the organiclight-emitting device OLED may be efficiently reduced and effectivelyprevented.

The encapsulation layer 300 may further include additional inorganiclayers and organic layers that alternate with each other, and the numberof times of stacking the inorganic and organic layers is not limited.

A protection film (not shown) is attached on a top surface of theencapsulation layer 300. In an exemplary embodiment where the protectionfilm has strong adhesion, when the protection film is removed, theencapsulation layer 300 may be delaminated. In this regard, by furtherdisposing the outermost fourth inorganic layer including AlOx and havingweak adhesion with respect to the protection film, the delaminationproblem may be reduced or effectively prevented.

FIG. 5 is a plane view illustrating another exemplary embodiment of anorganic light-emitting display apparatus 20 according to the invention.FIG. 6 is a cross-sectional view of the organic light-emitting displayapparatus 20 of FIG. 5, taken along line VI-VI′. FIG. 7 is across-sectional view of the organic light-emitting display apparatus 20of FIG. 5, taken along line VII-VII′. FIG. 8 is a magnifiedcross-sectional view illustrating portion P2 of FIG. 7.

Hereinafter, the exemplary embodiment of FIGS. 5 through 8 will now bedescribed with reference to differences with respect to the previousexemplary embodiment shown in FIGS. 1 through 4. Here, like referencenumerals in FIGS. 5 through 8 refer to the like elements in FIGS. 1through 4.

Referring to FIGS. 5 through 8, the organic light-emitting displayapparatus 20 includes a substrate 101, a display unit 2200 which definesan active area AA of the substrate 101 and/or the organic light-emittingdisplay apparatus 20, and an encapsulation layer 300 which encapsulatesthe display unit 2200.

Hereinafter, the display unit 2200 is described in detail with referenceto FIG. 7.

A buffer layer 201 may be disposed on the substrate 101.

A thin film transistor TFT may be disposed on the buffer layer 201. Thethin film transistor TFT may include an active layer 202, a gateelectrode 204, a source electrode 206 and a drain electrode 207.

A gate insulating layer 203 is disposed on the active layer 202. Thegate insulating layer 203 may correspond to an entire top surface of thesubstrate 101. That is, the gate insulating layer 203 may correspond tothe active area AA and an area outside of the active area AA.

The gate electrode 204 is disposed on the gate insulating layer 203.

An interlayer insulating layer 2205 is disposed on the gate electrode204. The interlayer insulating layer 2205 may correspond to the entiretop surface of the substrate 101. That is, the interlayer insulatinglayer 2205 may correspond to the active area AA and the area outside ofthe active area AA.

The interlayer insulating layer 2205 is disposed between the gateelectrode 204 and the source electrode 206, and between the gateelectrode 204 and the drain electrode 207 so as to respectively obtaininsulation therebetween. The interlayer insulating layer 2205 mayinclude an inorganic material including SiNx, SiO₂, or the like.

Stepped portions 2210 may be disposed in the area outside of the activearea AA and spaced apart from each other. The stepped portions 2210 maybe disposed between the gate insulating layer 203 and the interlayerinsulating layer 2205 in a cross-sectional thickness direction. Each ofthe stepped portions 2210 may include a metal layer. Each of the steppedportions 2210 may include a same material as that of the gate electrode204, the source electrode 206 and/or a pixel electrode 211. Thus, in anexemplary embodiment of manufacturing the organic light-emitting displayapparatus 10, the stepped portions 2210 may be formed by using the samemethod of forming the aforementioned electrodes so as to be in a samelayer as the respective electrode.

Concave-convex portions 2209 may be disposed in the area outside of theactive area AA. Since the interlayer insulating layer 2205 is disposedon the stepped portions 2210, the concave-convex portions 2209 may beformed by portions of the interlayer insulating layer 2205 due to a stepdifference between the stepped portions 2210 and the gate insulatinglayer 303.

A region in which the concave-convex portions 2209 are disposed may beconsidered to have an embossed shape. The concave-convex portions 2209are covered by the encapsulation layer 300. Due to the repeatingprotruding and recessed shape defined by the concave-convex portions2209, a contact area between the encapsulation layer 300 and theinterlayer insulating layer 2205 is increased. Thus, adhesion betweenthe encapsulation layer 300 and the interlayer insulating layer 2205 isimproved, so that delamination of the encapsulation layer 300 may bereduced or effectively prevented, and by doing so, penetration ofexternal moisture or oxygen to organic light-emitting device OLED may beefficiently reduced or effectively prevented

The source electrode 206 and the drain electrode 207 are disposed on theinterlayer insulating layer 2205.

The thin film transistor TFT is electrically connected to an organiclight-emitting device OLED and drives the organic light-emitting deviceOLED, and is covered by a passivation layer 208.

The passivation layer 208 may include an inorganic insulating layerand/or an organic insulating layer.

The organic light-emitting device OLED may be disposed on thepassivation layer 208, and may include a pixel electrode 211, anintermediate layer 214 and an opposite electrode 215.

A pixel defining layer 213 including an insulating material is disposedon the pixel electrode 211. An opening defined in the pixel defininglayer 213 exposes a predetermined region of the pixel electrode 211, andthe intermediate layer 214 including an organic EML is disposed on theexposed region of the pixel electrode 211 and in the opening defined inthe pixel defining layer 213.

The encapsulation layer 300 is disposed on the opposite electrode 215.The encapsulation layer 300 may include a first inorganic layer 301, afirst organic layer 302 and a second inorganic layer 303. Also, aprotective layer 220 may be further disposed between the encapsulationlayer 300 and the display unit 2200.

The protective layer 220 includes a capping layer 222 covering theopposite electrode 215, and a blocking layer 224 on the capping layer222.

The first inorganic layer 301 is disposed on the protective layer 220.In one exemplary embodiment, for example, the first inorganic layer 301may include AlOx.

The first organic layer 302 is disposed on the first inorganic layer 301and may have a preset cross-sectional thickness so as to planarize astep difference due to the pixel defining layer 213. A planar area ofthe first organic layer 302 may be less than that of the first inorganiclayer 301.

The second inorganic layer 303 may surround the first inorganic layer301 and the first organic layer 302. That is, the first organic layer302 is completely surrounded by the first inorganic layer 301 and thesecond inorganic layer 303, so that penetration of external moisture oroxygen may be efficiently reduced or effectively prevented.

The second inorganic layer 303 may include SiNx and may have a presetcross-sectional thickness formed in an exemplary embodiment ofmanufacturing the organic light-emitting display apparatus 10 such as byCVD.

A planar area of the second inorganic layer 303 may be greater than thatof the first inorganic layer 301 and may directly cover theconcave-convex portions 2209 in the area outside of the active area AA.

Also, the second inorganic layer 303 may include a same material as theinterlayer insulating layer 2205 and/or be in same layer as theinterlayer insulating layer 2205. That is, in an exemplary embodiment ofmanufacturing the organic light-emitting display apparatus 10, when thesecond inorganic layer 303 is formed of SiNx and the interlayerinsulating layer 2205 is also formed of SiNx, adhesion between thesecond inorganic layer 303 and the interlayer insulating layer 2205 maybe improved, so that adhesion between the second inorganic layer 303 andthe concave-convex portions 2209 may be improved. In this manner, thesecond inorganic layer 303 has a cross-sectional thickness sufficient tocover particles, so that, although a layer stress is increased,delamination of the second inorganic layer 303 may be reduced oreffectively prevented, and by doing so, penetration of external moistureor oxygen to the organic light-emitting device OLED may be efficientlyreduced or effectively prevented.

A second organic layer 304 and a third inorganic layer 305 may bedisposed on the second inorganic layer 303, and although notillustrated, a fourth inorganic layer (not shown) including of AlOx maybe disposed on an exterior surface of the encapsulation layer 300.

The second organic layer 304 may lessen a layer stress occurring in thefirst inorganic layer 301 and may evenly cover the particles or thelike.

The third inorganic layer 305 covers the second organic layer 304. Thethird inorganic layer 305 contacts a top surface of the second inorganiclayer 303 in the area outside of the active area AA.

The third inorganic layer 305 may include a same material as the secondinorganic layer 303. In one exemplary embodiment, for example, the thirdinorganic layer 305 may include SiNx. Thus, adhesion between the thirdinorganic layer 305 and the second inorganic layer 303 is improved, sothat penetration of external moisture or oxygen to the organiclight-emitting device OLED may be efficiently reduced or effectivelyprevented.

The encapsulation layer 300 may further include additional inorganiclayers and organic layers that alternate with each other, and the numberof times of stacking the inorganic and organic layers is not limited.

As described above, according to one or more of the above-describedexemplary embodiments of the invention, delamination of an encapsulationlayer may be reduced or effectively prevented so that penetration ofexternal moisture or oxygen to the organic light-emitting device OLEDmay be efficiently reduced or effectively prevented.

It should be understood that the exemplary embodiments described hereinshould be considered in a descriptive sense only and not for purposes oflimitation. Descriptions of features within each exemplary embodimentshould typically be considered as available for other similar featuresin other exemplary embodiments.

While one or more exemplary embodiments of the invention have beendescribed with reference to the figures, it will be understood by thoseof ordinary skill in the art that various changes in form and detailsmay be made therein without departing from the spirit and scope of theinvention as defined by the following claims.

What is claimed is:
 1. An organic light-emitting display apparatuscomprising: a substrate; a display unit which defines an active area ofthe substrate, the display unit comprising a thin film transistor and anorganic light-emitting device which are connected to each other in theactive area of the substrate; concave-convex portions protruded from thesubstrate in an area outside the active area and spaced apart from eachother; and an encapsulation layer covering the thin film transistor andthe organic light-emitting device in the active area of the substrate,to encapsulate the display unit on the substrate, wherein the thin filmtransistor comprises an active layer, a gate insulating layer on theactive layer, a gate electrode, a source electrode, a drain electrode,and an interlayer insulating layer between the gate electrode and thesource electrode, and between the gate electrode and the drainelectrode, the concave-convex portions comprise portions of the gateinsulating layer and the interlayer insulating layer, and theencapsulation layer covering the thin film transistor and the organiclight-emitting device in the active area of the substrate is extendedfrom the active area to the area outside the active area to contact theconcave-convex portions comprising the portions of the gate insulatinglayer and the interlayer insulating layer.
 2. The organic light-emittingdisplay apparatus of claim 1, wherein each of the concave-convexportions has a double-layer structure comprising the portions of thegate insulating layer and the interlayer insulating layer.
 3. Theorganic light-emitting display apparatus of claim 1, wherein theencapsulation layer comprises an inorganic layer, and the inorganiclayer contacts the concave-convex portions.
 4. The organiclight-emitting display apparatus of claim 3, wherein the inorganic layerand the interlayer insulating layer comprise a same material.
 5. Theorganic light-emitting display apparatus of claim 3, wherein theinorganic layer and the gate insulating layer comprise a same material.6. The organic light-emitting display apparatus of claim 1, wherein theencapsulation layer has a stacked structure comprising an organic layerand an inorganic layer, and the inorganic layer contacts theconcave-convex portions.
 7. The organic light-emitting display apparatusof claim 6, wherein the stacked structure comprises more than one of theorganic layer or the inorganic layer alternated with each other.
 8. Theorganic light-emitting display apparatus of claim 6, wherein theinorganic layer and the interlayer insulating layer comprise a samematerial.
 9. The organic light-emitting display apparatus of claim 6,wherein the inorganic layer and the gate insulating layer comprise asame material.
 10. The organic light-emitting display apparatus of claim1, further comprising a protective layer between the encapsulation layerand the display unit.